This invention relates to crystalline N-formimidoyl thienamycin and a process for its preparation.
The antibiotic N-formimidoyl thienamycin (I) is known, see for example, Belgium Pat. No. 848,545 (issued May 20, 1977): ##STR1## The crystalline form of N-formimidoyl theinamycin which is disclosed and claimed by this application is prepared from a lyophilized sample of I and is found to have unexpected stability in the solid state over the lyophilized form.